The guiding of them is not thy duty (O Muhammad), but Allah guideth whom He will. And whatsoever good thing ye spend, it is for yourselves, when ye spend not save in search of Allah's Countenance; and whatsoever good thing ye spend, it will be repaid to you in full, and ye will not be wronged. (Al-Baqarah : 272 - Medinan)

Make ready for them all thou canst of (armed) force and of horses tethered, that thereby ye may dismay the enemy of Allah and your enemy, and others beside them whom ye know not. Allah knoweth them. Whatsoever ye spend in the way of Allah it will be repaid to you in full, and ye will not be wronged. (Al-Anfal : 60 - Medinan)